Spectrum efficiency, capacity and coverage of wireless networks are being the main concern for wireless communication researchers. The performance of wireless channel has been progressed using the technology of MIMO with Alamouti space time block coding (Alamouti-STBC). This technology results in a significant improvement, which could further develop the overall performance of wireless Local Area Network (LANs) and Wide Area Network (WANs) to achieve better data rate and reliability of communication system. The purpose of this paper is to study and evaluate bit error rate performance of Alamouti-STBC coding with MIMO techniques using Zero Forcing (ZF) and Maximum Likelihood Detection (MLD) at receiver over Rayleigh fading channel. Simulation is carried out using MATLAB.
, , ابراهيم شتي , (3-2018)

Accreditation of laboratories has been a subject of considerable interest because product quality guarantee has become one of the prime factors to be considered at this present time of highly competitive industrial activity. Laboratories in the developing countries need to establish a new strategy on accreditation to be able to demonstrate the capability to compete internationally taking account of the difficulties, barriers, confidence and international acceptance. This paper intends to investigate the factors that lead to establishing a sustainable national accreditation body (NAB) and examine employees and management's attitudes and perceptions toward the development of a sustainable NAB in accordance with ISO/IEC 17011. The analysis has led to development of the main important factors that are directly affecting accreditation programmes in the developing countries. The Bayesian analyses have identified the main drivers of an accreditation model. The outcomes of the analyses are satisfactory because they correspond with the results of the theoretical framework
Tarek Elsmuai, (3-2014)

Because of the presence of sporadic high-intensity measurement noise (outliers),an adaptive algorithm for the robust estimation of parameters of linear dynamic discrete-time systems is proposed in this paper. first, the sorted data versus the normal quantiles is plotted, called QQ-plot. next the ε-contaminated normal distribution of noise is adopted. Then, a data classification procedure based on the QQ-plot approachcombined with the robustified data winsorization technique, is developed, the estimation of the unknown noise statistical parameters is solved. Moreover, an iterative procedure for estimating the contamination degree  , which originated from an ML classification, is also proposed. Thus, an ε- contaminated noise distribution is estimated and, the suboptimal maximum likelihood criterion is defined, and the system-parameter estimation problem is solved robustly, using the proposed recursive robust parameter estimation scheme.
Nasar Aldian Ambark Shashoa, Adel Saad Emhemmed, (3-2014)